Paper manufacture



Patented May 19, 1936 PAPER MANUFACTURE Harold Robert Rafton, Andov er, Mass., assig'nor to Rafl'old Process Corporation, a corporation of Massachusetts No Drawing.

Application May 2, 1933,

Serial No. 669,065

17 Claims.

This invention relates to the manufacture of paper filled with alkaline filler.

The principal object of this invention is the manufacture of paper filled with alkaline filler employing an emulsion of substantially'water insoluble sizing material substantially inert to alkaline filler, such as paramn. i

A further object is the employment of this sizing'material in the form of a substantially nonbreakable emulsion, but without the use of mutually precipitating soluble agents to concentrate the disperse phase of the emulsion.

A further object is the employment of this sizing material in the form of an emulsion made with a substantially water insoluble type emulsifying agent, but without the use of mutually precipitatingsoluble agents to serve to associate the emulsion with the fibre.

Other objects and advantages of this invention will become apparent during the course of the following description.

This application is a continuation in part of my copending application Serial No. 487,377, filed October 8, 1930.

In my Patent No. 1,803,645, issued May 5, 1931, I describe a method of sizing paper filled with an alkaline filler, such as a carbonate, by mixing with fibrous material and a carbonate a substantially nonbreakable paraflin emulsion in conjunction with two mutually precipitating soluble agents which serve to concentrate the disperse phase of said emulsion, and following this by the addition to the mix of a restoring agent under conditions favoring the minimizing of the time and/or intimacy of contact of the constituents of the mix. In my Patent No. 1,803,648, issued May 5, 1931, I describe a process in some respects similar to the above with the exception, however, that one of the mutually precipitating soluble agents is originally omitted and is later added, in lieu of a restoring agent, under conditions favoring the minimizing of the time and/or intimacy of contact of the constituents of the mix. In this connection cross reference is also made to my Patent No. 1,803,644, issued May 5, 1931, which likewise deals with a substantially nonbreakable paraflin emulsion in sizing paper.

In my Patent No. 1,803,651, issued May 5, 1931, I described a method of sizing paper filled with an alkaline filler such as a carbonate, by mixing with fibrous material and a carbonate a parafiin emulsion made wtih a substantially water'insoluble type emulsifying agent in conjunction with two mutually precipitating soluble agents which serve to associate said emulsion with the fibre,

and following this by the addition to the mix of a restoring agent under conditions favoring the minimizing of the time and/or intimacy of contact of the constituents of the mix. In my Patent No. 1,803,652, issued May 5, 1931, I described a 5 process in some respects similar to the above with the exception, however, that one of the mutually precipitating soluble agents is originally omitted and is later added, in lieu of a restoring agent, under conditions favoring the minimizing of the 10 time and/or intimacy of contact of the constituents of the mix.

It will be noted that in the patents referred to above, two mutually precipitating soluble agents are employed in conjunction with the 15 emulsions.

Whereas excellent results are obtained by the above described methods, I have found that in some cases in the manufacture of sized paper filled with alkaline filler, it appears to be feasible to obtain satisfactory results with emulsions similar to those used therein, but without the use of two mutually precipitating soluble agents in conjunction therewith.

It appears, however, to be desirable in most of 25 these cases to use one of the mutually precipitating soluble agents in the absence of the other, and this agent should preferably be an acidic agent, for example alum.

My invention, therefore, may in its preferred 30 form be briefly stated as follows: I provide a paper mix comprising fibrous material, alkaline filler, and an emulsion of a substantially water insoluble sizing material substantially inert to alkaline filler, the emulsion being either substantially nonbreakable or one made with a substantially water insoluble type emulsifying agent,but in the absence of a soluble agent precipitable by an acidic material; then I preferably introduce an acidic material preferably under conditions favoring the minimizing of the time and/or intimacy of contact of the constituents of the mix 01 on the webforming device, and subsequently dry the web formed from said mix. 45

In the preferred practice of my invention I mix with suitable fibrous material -in the beater a 'paraflin emulsion either substantially nonbreakable, or made with a substantially waterinsoluble type emulsifying agent, and add alkaline filler. Such a mix may be run ofi on the paper machine, but I prefer to add also an acidic material such as alum. Such alum may be added in the beater, but I prefer to add either all or. at least part of it subsequent thereto which is under conditions favoring the minimizing of the 55 time of contact of the constituents of the mix, for example in the last stuff chest in the papermaking operation, which is usually the machine chest; and my greater preference is to add it under conditions favoring the minimizing of the time and intimacy of contact of the constituents of the mix, for example at the dilute stage of the papermaking process, that is, at or subsequent to the mixing box and prior to web formation. The alkaline filler and/or the paraflin emulsion may, as stated, he added either in the beater or the like, or if desired under conditions favoring the of the time and/or intimacy of contact of the constituents of the mix as described above. In certain cases I find it desirable to add the alum, and/or the alkaline filler and/or emulsion even'on the web-forming device itself. In this connection cross reference is made to my copending applications Serial No. 501,674, filed December 11, 1930, now Patent No. 1,922,325, dated August 15, 1933, and Serial No. 534,462, filed May 1, 1931, now Patent No. 1,914,526 dated June 20, 1933.

By the employment of my method I find that .a satisfactorily sized paper filled with alkaline filler is made even though two mutually precipitating soluble agents are not employed.

An illustrative furnish which may advantageously be used in practicing my invention is as follows:

Materials added in the beater V a Pounds Fibrous furnish, (e. g. sulphite and soda nulps) 1700 .Parafiln (added in the form of a substantially nonbreakable emulsion) 40 Alkaline filler (for example calcium carbonate) on dilation Pounds Alum (ordinary A]2(SO4)3.18H2O) 50 Another illustrative furnish is as follows:

Materials added in the beater Pounds Fibrous furnish (e. g. approximately equal parts of sulphite, soda and old paper Alkaline filler (for example calcium carbonate) 250 Material added proportionately and continuously on dilution Pounds Alum (ordinary Ah(SO4)3.18H:O) 55 In the above formulae, the weights of alka-' line filler refer to the bone dry basis, the weights of all other ingredients being given on the air dry basis.

In either of the above fumishes starch may also be used. It may be conveniently added to the heater or subsequent thereto, for example at the dilute stage if desired.

The illustrative furnishes given above produce satisfactorily sized paper, and as will be apparent the sizing can be increased or decreased by varying the relative proportions of the materials used. It is to be understood, however, that these 300 llaterial added proportionately and continuously examplesare illustrative only and not limiting as the proportions of ingredients as well as their order of mixing and point of addition can be widely varied and still have satisfactorily sized paper produced. A 5

When I employ the term 'parafiin" herein, I mean parafi'in wax, which. is solid at ordinary or room temperature. I do not mean to restrict myself only to the paraflin hydrocarbons,' but mean to include in this term all the hydrocarbons of a waxy nature substantially unsaponifiable and inert to acidic and alkaline materials under ordinary conditions of temperature and pressure, whether derived from petroleum, shale, lignite, earth wax, or other natural or artificial sources. I do not, however, mean to include in this term material of a pitchy nature, such as bitumen or asphalt.

Relative to the paraifin emulsion employed, both types mentioned herein have been previ ously described by me in full in my above mentioned already issued patents, to which reference is made in this connection, and it will therefore not be necessary to repeat the description here.

However, it can be stated that of the various methods of manufacturing emulsions mentioned in the said patents, I prefer to use, in the manufacture ofthe substantially nonbreakable type, a gum as an emulsifying agent, e. g. gum arabic or gum ghatti, preferably the latter. I have found that emulsions containing from approximately 2 to 5% more or less gum ghatti on the weight of the paraiiln are suitable, and I prefer to make this emulsion in a homogenizer. with reference to the emulsion made with a substantially. water insoluble type emulsifying agent, my

, preferred emulsion is made with a colloidal clay,

such as bentonite, and I have found that 5 to 15% bentonite, more or less, on the weight of the paraflin is a suitable amount of emulsifying agent to use, and that a suitable machine in which to make such emulsion is a colloid mill.

As substantially water insoluble sizing agent I may employ instead of paraflin other materials which similarly are substantially inert to alkaline filler such for example as other hydrocarbons and the like, and these may if desired be thermoplastic. Many specific examples of materials substantially inert to alkaline filler are of course well known in the art, such for instance as synthetic resinous products made for example by condensation, mentioned on page 3, lines 102-104 of my Patent No. 1,957,474, filed July 8, 1932, and issued May 8, 1934; and rubber, together with the softeners therefor such as petrolatum and cumarone resin, all mentioned in Patent No. 1,914,527 filed May 4, 1931, and issued June 20, 1933, to myself and Arthur Minard Brooks, the latter materials being specifically mentioned on page 4, lines and 81 of said patent. The substantial inertness of 60 rubber, petrolatum, and cumarone resin to alkaline materials is of course a matter of common knowledge. As to cumarone resin (frequently called paracumaron") this is stated by Ellis to be unaffected by alkalies" on page 32, line 1 and 65 footnote 5, of his Synthetic Resins and their Plastics (The Chemical Catalog Co. Inc., N. Y. 1923). As to petrolatum, that is synonymous with the term Vaseline (as can be seen by reference to Allen's Commercial Organic Anal- 70 .ysis, 5th edition, vol. 111, heading of the last paragraph on page 151, (P. Blakistons Son 8: Co., Philadelphia) Vaseline is listed by Perldn and Kipping under Parafllns of commercial importance on page 70, line 17, of Organic Chemistry, 5

v a considerable amount of. prepared fibre and asphalt.

material of a pitchy nature, such as bitumen or As an acidic material, instead of alum I may employ other metallic-salts such as salts of zinc, tin, .or the like, or other salts of aluminum such as the chloride, but I prefer alum. By the term alkaline filler I mean substantially water insoluble filter which when agitated in contact with freshly boiled distilled water, say for an hour, will impart a pH value to such water greater than 7.0, that is, which will be on the alkaline side of the neutral point. Among fillers included in this group may be mentioned calcium carbonate, of which lime mud from the causticizing process is one form; calcium carbonate magnesium basic carbonate employed in the paper disclosed in my U. S. Patent No. 1,595,416, of August 10, 1926; calcium carbonate magnesium hydroxide disclosed in my U. S. Patent No. 1,415,- 391 of May 9, 1922; and other substantially water insoluble normal or basic carbonates of alkaline earth metals, (which expression is herein intended to include magnesium), or compounds, double salts, or physically associated mixtures of these with one or more other acid soluble materials of a substantially water insoluble nature. By the term alkaline filler I also intend to include fibrous material and/or other material such as paper coating constituents or the like,

containing one or more compounds of the character referred to, such as old papers" or similar papers, broke, or the like.

When I use the word paper herein, I useit in the broad sense to include products of manufacture of all types and of all weights and thicknesses, which contain as an essential constituent which are capable of being produced on a Fourdrinier, cylinder, or other forming, felting, shaping or molding machine.

i It is sometimes desirable to use in the manufacture of paper a small amount of substantially water insoluble sizing material, such for example as would not impart a substantial degree of sizing to the resulting paper, for the purpose of imparting certain characteristics to the paper stock and/or the final paper other than sizing.

It is to be understood, therefore, that the production of substantially unsized paper by my process, and the paper thereby produced, falls within the scope of my invention.

While I have described in detail the preferred embodiments of my invention, it is to be understood that the details of procedure, the propor- 17101151101 ingredients, and the arrangement of steps may be widely varied without departing from the spirit of my invention or the scope of the subjoined claims.

I claim:

1. A method of manufacturing paper filled with alkaline filler which comprises providing a fibrous mix comprising alkaline filler, a substantially nonbreakable emulsion of substantially water insoluble sizing material substantially inert to alconstitute a size, forminga kaline filler, and being substantially free from any precipitate serving to concentrate the disperse' phase of said emulsion formed by two-'mu tually precipitable soluble agents including any such precipitate which of itself would constitute a size, forming a web from said mix, and drying said web.

2. A method of manufacturing paper filled with alkaline filler which comprises providing a fibrous mix. comprising alkaline filler, a substantially nonbreakable emulsion of substantially water in.- soluble sizing'material substantially inert to alkaline 'filler, acidic material, and: being ,substamtially' freefrom afsoliible, agent rcipi v table withsaidacidicmaterial by recipitafion rew th'woii q mm 9. f; 11; a 9 1M- ing any such precipitate whic ,itselfwould and drying said welt};

3. A method of w alkaline filler which comprises providing a' fibrous mix comprising alkaline filler, a substantially nonbreakable emulsion of substantially wateri'nsohb, ble sizing material substantially inert to alkaline filler, acidic material, and being substantially free from a soluble agent mutually precipitable with said acidic material which by precipitation therewith would form a precipitate including any such precipitate which of itself would constitute a size, said acidic material being added to said mix under conditions favoring the minimizing of the time of contact of the constituents of the mix, forming a web from said mix, and drying said web.

4. A method of manufacturing paper filled with alkaline filler which comprises providing a fibrousmix comprising alkaline filler, a substantially nonbreakable paraflin emulsion, and being substantially free from a precipitate serving to concentrate the disperse phase of said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would constitute a size, forming a web from said mix, and drying said web.

5. A method of manufacturing paper filled with alkaline filler which comprises providing a fibrous web comprising alkaline filler, a substantially nonbreakable emulsion of substantially water insoluble sizing material substantially inert to alkaline filler, and being substantially free from any precipitate serving to concentrate the disperse phase of said emulsion formed by two mutually precipitable soluble agents including any such precipitate whichof itself would constitute a size, and drying said web.

6. A method of manufacturing paper filled with alkaline filler which comprises providing a fibrous web comprising alkaline filler, a substantially nonbreakable emulsion of substantially water insoluble sizing material substantially inert to alkaline filler, acidic material, and being substantially free from a soluble agent mutually precipitable with said acidic material which by precipitation therewith would torm a precipitate including any such precipitate which of itself would constitute a size, and drying said web.

'7? A method of manufacturing paper filled with to alkaline filler, consisting ofthe substantially nonbreakable type and the substantially water insoluble emulsifier type, and being substantially free from any precipitate serving to concentrate the disperse phase of said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would constitute a size, and drying said web.

8. -A method of manufacturing paper filled with alkaline filler which comprises providing a fibrous mix comprising alkaline filler, a substantially water insoluble emulsifier type emulsion of substanany such precipitate which of itself constitute a size, and drying said web.

would constitute a size, forming a web from said and drying said web. QJA'method of manufacturing paper fillettwith alkaline filler which comprises providing a fibrous web comprising alkaline filler, a substantially "'water'insoluble emulsifier type emukion of substantially water insoluble sizing material substantially inert to alkaline filler, and being substantially free from any precipitate serving to concentrate the disperse phase of said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would 10. A method of manufacturing paper filled with alkaline filler which comprises providing a fibrous web comprising alkaline filler, a substantially water insoluble emulsifier type emulsion of substantially water insoluble sizing material substantially inert to alkaline filler, acidic material, and being substantially free from a soluble agent mutually precipitable with said acidic material which by precipitation therewith would form a precipitate including any such precipitate which of itself would constitute a size, and drying said web.

ll. A paper comprising fibrous material, alka line filler, substantially water insoluble sizing material substantially inert to alkaline filler derived from a substantially nonbreakable emulsion therethereof, and being substantially free from any precipitate having served to concentrate said substantially water insoluble sizing material from said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would have constituted a size.

13. A paper comprising fibrous material, alkaline filler, substantially water insoluble sizing materlal substantially inert to alkaline filler derived from a gum ghatti emulsion thereof, and being substantially free from any precipitate having served to concentrate said substantially water in-.

' soluble sizing material from said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would have constituted a size.

14. A paper comprising fibrous material, alkaline filler, substantially water insoluble sizing material substantially inert to alkaline filler derived from a substantially water insoluble emulsifier type emulsion thereof, and being substantially free from any precipitate having served'to concentrate said substantially water insoluble sizing material from said emulsion formed by two "mutually precipitable soluble agents including any such precipitate which of itself would have constituted a size.

15. A paper comprising fibrous material, substantially unsaponifiable substantially water insoluble sizing material derived from a substantially nonbreakable emulsion thereof, and being substantially free from any precipitate having served to concentrate said substantially water insoluble sizing material from said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would have constituted a size.

16. A paper comprising fibrous material, paraffin derived from a substantially nonbreakable emulsion thereof, and being substantially free from any precipitate having served to concentrate said paraflin from said emulsion formed by two mutually precipitable soluble agents including any such precipitate which of itself would have con- HAROLD ROBERT RAFTON. 

